Metal transport pans, commonly made of stainless steel are extensively used for food serving and transport in restaurants and in institutions such as hospitals. The transport pan can be removably positioned in a steam table, or mounted in some other holder.
The metal transport pans are typically formed from an initially flat sheet of metal by one or more draws between a punch and die to have a perimetric wall structure and an outwardly-extending flange at the top thereof.
In determining the shape and dimensions of the pan, it is necessary to have the pan dimensioned to have good drawing features and to also have a shape to be usable for the intended purpose. In order to have a pan which will stack with other similar pans for storage in partially nested relation, it is necessary for the perimetric wall structure to have a downward and inward taper. However, it is desirable to minimize this taper to maximize the dimension at the bottom of the pan to achieve a maximum holding capacity therefor.
Applicants' assignee manufactures a transport pan of stainless steel, Product No. F2004, which is of a rectangular shape having front, rear and end side walls, all of which taper downwardly and inwardly at a moderately large angle from a surrounding outwardly-extending top flange. For a short distance below the top flange, the tapered side walls are formed with an outward offset to form a continuous internal shelf for support of a cover for the pan. Because of the taper, two identical pans can nest partially one within the other. The outward offset which forms an outwardly-protruding ridge does not prevent jamming between the pans because the outwardly-protruding continuous ridge does not rest on the flange of the subjacent pan to prevent jamming between the tapered walls of the nested pans. The angle of wall taper is sufficiently large that the interior periphery of the flange of the subjacent pan has a perimetric dimension larger than that of the outwardly-protruding ridge of the uppermost pan, so that the ridge will not contact the subjacent pan flange and prevent full nesting of the pans.
Another pan of applicants' assignee, No. F-1314, is of generally the same construction as the pan described in the preceding paragraph, except that the side walls have a very slight taper and, when two similar pans are nested, the pans jam together before the outwardly-protruding ridge on one pan reaches the flange of the subjacent pan. As a result, one pan can jam within the other and render separation thereof extremely difficult and there is no coaction between a ridge and flange of nested pans to prevent jamming.
Another commercially available pan of a generally rectangular configuration has front, rear and end side walls, with an outwardly-extending top flange and with the side walls being joined at curved corners. Both the flanges and the uppermost part of the curved corners are concavely deformed, apparently for strengthening of the flange. The deformations formed in the curved corners of one pan fit within the deformations of a subjacent pan when the pans, which have a relatively slight downward and inward taper to the side walls, nest one within the other. The deformations in the curved corners have a taper similar to that of the side walls, so that there is a tight fit between the curved corner deformations and the side walls of substantially fully nested pans. As a result, the pans can be firmly jammed together and it is extremely difficult to separate one pan from the other.
Applicants' assignee has manufactured and sold a round metal bowl, with the perimetric wall structure having a downward and inward taper and an outwardly-extending top flange. The taper of the bowl enables substantially full nesting of such a bowl within a subjacent bowl of the same dimensions. In order to prevent jamming of the bowls to each other, the perimetric wall structure has three equally circumferentially spaced-apart dimples at a distance below the top flange to provide outward protrusions in the perimetric wall structure. These protrusions can engage a top flange of a subjacent bowl and prevent full nesting and maintain the bowls in a nonjamming relation. The use of the dimples provided a bowl structure which would prevent jamming of nested bowls. However, the formation of a plurality of dimples in the tapered perimetric wall structure of a bowl or pan is not cost-effective because of the additional number of operations required to form the dimples.
The prior art is not known to disclose a transport pan with a perimetric wall structure including curved corners having a slight inward taper to facilitate nesting of a plurality of the pans and which has a nonjamming feature by forming an upper part of the curved corners immediately below the top flange of the pan, with a straight wall at a right angle to the top flange, rather than a tapered wall, in the pan-forming process. This results in localized, outwardly-extending ridges at the curved corners of the pan which directly underlie the top flange of the pan whereby a pan may partially nest within a subjacent pan of the same dimensions and with the localized outwardly-protruding ridges engaging and resting on the top flange of the subjacent pan. This limits the metal-to-metal contact between the two pans to that between the ridges and the top flanges and prevents any contact between the tapered walls of the pans to avoid jamming of the pans.